I'm also curious on how to run the beta client on a jailbroken device. My question is legit, but don't answer if it shouldn't be answered

I have an official access to the beta programme on my old iPhone 4, but recently got a new iPhone 5, so I can either run both devices at the same time with different accounts, or try the new jailbreak stuff for the iphone 5 and try to run the beta there, but unless I know it's possible and easy and won't break anything, I'll probably won't even jailbreak my device.

Weird thing. Couldn't find AppSync (the official site closed, and didn't trust other sites). Installed AppCake. Then found out iFunbox, but had no need to use it. Just clicked on the link from the beta email and it just installed. No idea if it worked just with the jailbreak, or because of AppCake installed, but again didn't even use iFunBox or used AppCake to install anything.